Human failings and deadly viruses are a bad mix

Despite their ‘superpowers,’ COVID and African swine fever rely on humans to spread, says vet

An electric fence along a road in Germany near its border with Poland — one of many measures taken to contain African swine fever.

Glacier FarmMedia – With the spread of both COVID-19 and African swine fever, humans can be their own worst enemies.

That message was delivered by Ontario veterinarian during the recent virtual farm show.

Dr. George Charbonneau outlined the “superpowers” of the two viruses and offered his take on where humans have been successful and not so successful in preventing their spread.

Although African swine fever has a high mortality rate — some outbreaks kill up to 100 per cent of infected pigs — it doesn’t necessarily spread quickly, he said. In some cases, it appears only 30 per cent of those exposed contracted the virus. (This is different from something like Porcine Reproductive and Respiratory Syndrome, which has a close to 100 per cent infection rate.)

This, though, is actually a “superpower” for African swine fever when it comes to efforts to control it. If a producer gets it in their barn, it could take up to three weeks before they know it’s there.

But its most significant superpower is survivability. It can persist on cured pork bellies for 60 days, and on cured loins for 83 days.

“So someone brings home a snack of Uncle Ernie’s kielbasa and everybody has to have a taste,” Charbonneau said.

Those people can then get fragments on their clothes and go to the barn, or discard the leftovers somewhere where they can be accessed by hogs.

“These pork products from other regions are extremely dangerous.”

African swine fever also persists on the dead pig’s carcass, surviving in the bones for up to three months at 20 C, and in the skin for up to six months at 4 C. If an unsuspecting farmer buries a dead pig before realizing it died of African swine fever, things can get complicated.

“One of the lessons learned is that you can remove the carcass but you really have to sanitize the soil,” Charbonneau said.

As well, recent research has shown it can survive for weeks in a wide range of feed products.

Controlling COVID

COVID-19, meanwhile, is in the middle of the pack for infection rate, falling below measles and chickenpox on the list.

When it comes to “tenacity… this organism is a bit of a slouch compared to ASF.”

If conditions are really good, it can survive up to 28 days on some surfaces. But it will very likely perish within a few hours on many surfaces or within two to three days on most others.

COVID-19’s main superpower is “stealth,” he said.

If someone gets a high dose of exposure, it doesn’t typically take too long for it to incubate and for symptoms to show up in humans. But if it’s a low dose of exposure, or especially if the person exposed is asymptomatic (which happens frequently), then the incubation and development of symptoms take place without being noticed and suddenly there’s a significant outbreak.

Humans have shown themselves to be their own worst enemies, said Charbonneau.

A German veterinarian, having tracked African swine fever from its introduction into the Eastern European nation of Georgia and subsequent transmission into Europe, said the virus “spreads about as quickly as you can drive a truck down the road.”

And then when prices for pork products fell in some countries, people would import the infected products into the unaffected regions — despite warnings from health officials not to do so.

“It’s people’s stupidity spreading the virus rather than a bunch of wild pigs running around the countryside.”

Refusing to heed the advice of public health specialists has also been a factor in COVID’s spread.

There are also similarities for other containment methods.

Europe is using controlled access zones on ASF-affected swine production facilities — a measure that producers and animal health officials are prepared to also implement in Canada if the virus is detected here. This includes double-walled perimeter barriers designed to keep infected pigs away from the wild population, and away from human visitors who aren’t cleared to enter.

This strength of barrier, and access protocol, is already in place for COVID-19.

“Anybody who visits somebody at a long-term care home knows we’re doing the same thing,” said Charbonneau.

Incoming and outgoing supplies and equipment must also be disinfected to a similar degree under both the ASF and COVID protocols. And quarantine regimes are essentially the same for COVID as they would be for African swine fever, if it is detected here.

Charbonneau said he is not aware of any vaccine being developed for African swine fever and it’s unlikely there would be a call in North America for vaccinating swine herds. That’s because any vaccination would throw complications into Canadian and American efforts to enact strict testing protocols as a means of proving to pork-buying markets that their supplies are virus free.

This article was originally published at Farmtario.

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